Method for short or open fault handling of an electric propulsion thruster neutralizer contact

Abstract

This invention proposes a method for handling short-circuit or open-circuit faults in the neutralizer contacts of an electric propulsion thruster, belonging to the field of electric propulsion. It solves the problem that traditional methods, when short-circuit or open-circuit faults occur in the neutralizer contacts of an electric propulsion thruster, only allow for adjusting flow rate and electrical parameters, lacking effective on-orbit handling measures, leading to neutralizer and even the entire thruster failure. It includes: initiating closed-loop control of the storage and supply unit pressure and flow rate; simultaneously opening the neutralizer heating, contact power supply, and neutralizer ignition power supply; performing normal discharge chamber ignition; after successful ignition, shutting off the cathode heating and ignition power supply, and setting the cathode flow rate to the normal flow rate; after the discharge chamber is ignited, waiting for a time T1, opening the screen grid acceleration power supply, using an external beam electric field to replace the contact electrode function, and extracting electrons; initiating flash protection, increasing the number of flashes within a preset time to the fault handling value; determining whether the acceleration current is less than or equal to a preset threshold, and if so, determining that the neutralizer ignition is successful.

Description

Technical Field

[0001] This invention belongs to the field of electric propulsion, and in particular relates to a method for handling short circuit or open circuit faults of the neutralizing electrode of an electric propulsion thruster. Background Technology

[0002] Currently, there are many types of propulsion systems for in-orbit flight. Among them, electric propulsion systems have developed rapidly in recent years due to their high specific impulse, especially Hall effect electric propulsion systems and ion electric propulsion systems, which are frequently used in geostationary orbit satellite platforms to perform tasks such as north-south position maintenance, attitude control (momentum wheel unloading), orbit control, and even geostationary orbit transfer. In addition, electric propulsion systems can accomplish tasks that conventional propulsion systems cannot, such as deep space exploration, interstellar travel and other missions requiring large ΔV values, as well as precise attitude control of satellites and microsatellites and satellite constellation networking control.

[0003] like Figure 2 As shown, the ion thruster, a key component of the electric propulsion system, uses electrical energy to ionize and accelerate the working propellant, thereby generating thrust. Ignition of the ion thruster involves complex gas supply from the storage and supply unit and power supply regulation from the power processing unit. The thruster ignition and output thrust are achieved through steps such as neutralizer ignition, cathode and anode ignition, and grid beam extraction. Figure 3 As shown.

[0004] like Figure 4 As shown, the ion thruster consists of a hollow cathode, a neutralizer, an anode, a screen grid, an accelerating grid, and a magnetic field. After being heated, the hollow cathode emits electrons. These electrons enter the anode and move along a specific trajectory under the constraint of the magnetic field, colliding with the xenon gas inside the anode. This causes the xenon particles to lose electrons, forming positively charged ions. These xenon ions are accelerated and ejected under the action of the screen grid (+1000V) and the accelerating grid (-200V), forming a high-speed beam that generates thrust.

[0005] like Figure 5 As shown, the neutralizer is the core component of the ion thruster. It maintains the overall electrical neutrality of the spacecraft and ejected material by neutralizing the electrons it emits with the positively charged ion beam. Its working principle involves heating the cathode emitter material to a certain temperature, causing the material surface to spontaneously emit electrons, ionizing the xenon gas in the emission area. The ionized ions continuously bombard the emitter, maintaining its operating temperature through energy deposition and continuously generating electrons. The contact electrode creates a localized high-potential region within the neutralizer, enabling a stable and efficient output of the electron flow. A common neutralizer failure is a short circuit or open circuit in the contact electrode, which can cause the neutralizer and even the thruster to fail. Therefore, designing a new ignition strategy to ensure normal electron extraction even in the event of a contact electrode failure, thus guaranteeing normal ignition and operation of the ion thruster, is of great significance in addressing the problem at the system level and significantly improving the reliability of electric propulsion. Summary of the Invention

[0006] In view of this, the present invention aims to propose a method for handling short circuit or open circuit faults of neutralizer contacts in electric propulsion thrusters, in order to solve the problem that when short circuit or open circuit faults occur in the neutralizer contacts of electric propulsion thrusters, traditional methods can only adjust the flow rate and electrical parameters and lack effective on-orbit handling means, leading to the failure of the neutralizer and even the entire thruster.

[0007] To achieve the above objectives, the present invention adopts the following technical solution to provide a method for handling short-circuit or open-circuit faults in the neutralizer contact poles of an electric propulsion thruster, comprising: S1. Start the closed-loop control of pressure and flow of the storage and supply unit; S2. Simultaneously turn on the neutralizer heating, contact power and neutralizer ignition power; S3. Perform normal ignition in the discharge chamber; after successful ignition, turn off the cathode heating and ignition power, and set the cathode flow rate to the normal flow rate. S4. After the discharge chamber is ignited, after a waiting time T1, the screen grid acceleration power supply is opened, and the external beam electric field replaces the contact electrode to draw out the neutralizer electrons. S5. Activate the flashing protection and increase the number of flashes within a preset time to the fault handling value; S6. Determine whether the accelerating current is less than or equal to the preset threshold. If so, determine that the neutralizer ignition is successful. S7. Ignition successful. Turn off the neutralizer heating and neutralizer ignition power.

[0008] Furthermore, in S4, time T1 ranges from 350s to 420s.

[0009] Furthermore, time T1 is 390s.

[0010] Furthermore, in S5, the fault handling value is 10 to 20 times.

[0011] Furthermore, the fault handling value is 16 times.

[0012] Furthermore, the preset time is 50s to 70s.

[0013] Furthermore, the preset time is 60 seconds.

[0014] Furthermore, in S6, the preset threshold is 21mA.

[0015] Beneficial effects: 1. This method starts from the electric propulsion system level, uses an external beam electric field to replace the contact electrode, and achieves stable ignition of the ion thruster by adjusting the ignition parameters and ignition process, thereby significantly improving the reliability of the electric propulsion system.

[0016] 2. When a short circuit or open circuit fault occurs at the contact electrode, this method can achieve normal lead-out of neutralizer electronics without relying on the contact electrode itself. By reconstructing the ignition timing, relaxing the flashover protection criterion, and using the accelerating current as the criterion for successful neutralizer ignition, the risk of the entire thruster failing due to a single point fault at the contact electrode is avoided. This significantly improves the autonomy and success rate of on-orbit fault handling in electric propulsion systems and extends the effective working life of the thruster. Attached Figure Description

[0017] Figure 1 Flowchart of ion thruster ignition in case of neutralizer contact electrode failure; Figure 2 Diagram of electric propulsion system composition; Figure 3 The normal electric propulsion ignition process; Figure 4 Schematic diagram of an ion thruster; Figure 5 Schematic diagram of the cathode structure.

[0018] Figure 5 In the middle: 1. Emitter region; 2. Cavity region; 3. Contact region; 4. Anode region. Detailed Implementation Specific implementation method one: Referring to the accompanying drawings, this embodiment provides a method for handling short-circuit or open-circuit faults in the neutralizer contacts of an electric propulsion thruster, including: S1. Start the closed-loop control of pressure and flow of the storage and supply unit; S2. Simultaneously turn on the neutralizer heating, contact power and neutralizer ignition power; S3. Perform normal ignition in the discharge chamber; after successful ignition, turn off the cathode heating and ignition power, and set the cathode flow rate to the normal flow rate. S4. After the discharge chamber is ignited, wait for 350s to 420s, then open the grid acceleration power supply and use the external beam electric field to replace the contact electrode to extract electrons; preferably 390s. S5. Activate the flashing protection, increasing the number of flashes within a preset time from 3-10 times to a fault handling value of 10-20 times, preferably 16 times, with a preset time of 50-70 seconds; S6. Determine whether the accelerating current is less than or equal to a preset threshold. If so, determine that the neutralizer ignition is successful. The preset threshold is 10mA to 30mA, preferably 21mA.

[0020] S7. Ignition successful. Turn off the neutralizer heating and neutralizer ignition power.

[0021] Neutralizer contact electrode fault handling process as follows Figure 1As shown, the difference from the normal ignition process is: The neutralizer heating power, contact power, and ignition power are turned on simultaneously. In the original ignition process, the contact power and ignition power were turned on 180 seconds after the neutralizer was heated. The instructions are simplified, and the ignition power is turned on earlier, which is conducive to the successful ignition of the neutralizer. The determination of whether the neutralizer ignited successfully is not performed; After the discharge chamber is successfully ignited, wait 390 seconds to provide sufficient heating time for the cathode emitter material of the neutralizer, thereby improving its electron emission capability. After the beam is extracted by the loading of the grid acceleration power supply, a local high voltage electric field can be formed, which acts as a holding electrode to ensure that the electrons emitted by the neutralizer are continuously extracted. The flicker protection is activated, and the cumulative flicker count within 1 minute is changed from 5 to 16. This is because once the flicker count reaches the specified value, the grid acceleration power supply is shut off, stopping the beam current extraction. It restarts after 10 seconds. During the 10-second beam interruption, the external high-voltage electric field disappears, and the neutralizer cannot maintain its ignition state. By relaxing the criteria, the possibility of the neutralizer extinguishing its arc is reduced. Using the acceleration current parameter as the criterion, if the acceleration current is ≤21mA, it indicates that the beam extraction is normal and has been neutralized, and the neutralizer ignites normally. In the case of a contact electrode failure, the contact current ≥1A is no longer used as the criterion for successful neutralizer ignition. 21mA is the upper limit of the acceleration current during normal ignition. If the neutralizer fails to ignite, it will be positively charged.

[0022] Example 1) After receiving the electric propulsion ignition command, the electric propulsion control software begins the electric propulsion ignition process; 2) The electric propulsion control software starts the closed-loop control of pressure and flow in the storage and supply unit. After the pressure and flow reach the set points, step 3) begins. 3) The electric propulsion control software sends instructions to the power processing unit to turn on the neutralizer heating power supply to heat the electric thruster neutralizer, turn on the contact power supply, and turn on the neutralizer ignition power supply. 4) Perform the normal discharge chamber ignition process, including turning on the cathode heating power supply to heat the electric thruster cathode, turning on the cathode ignition power supply, and turning on the anode power supply; 5) The electric propulsion control software judges the anode power supply output current collected by the power processing unit. The anode power supply output current is 3.5A, which is greater than the judgment threshold of 3A, indicating that the discharge chamber is ignited. The electric propulsion control software sends a command to the power processing unit to shut down the cathode heating and ignition power. The electric propulsion control software sets the cathode flow rate to the normal flow rate. 6) After the discharge chamber is ignited, wait 390 seconds, and the electric propulsion control software sends a command to the power processing unit to open the screen grid and accelerate the power supply. 7) The electric propulsion control software activates flash protection, changing the cumulative number of flashes within 60 seconds from 5 to 16. 8) The electric propulsion control software judges the acceleration current collected by the power processing unit. The electric propulsion acceleration current is 9mA, which is less than the judgment threshold of 21mA, indicating that the neutralizer ignition is successful. 9) The electric propulsion control software sends instructions to the power processing unit to shut down the neutralizer heater and neutralizer ignition power.

[0023] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A method for handling short or open fault conditions in an electric propulsion thruster neutralizer contact, comprising: Includes the following steps: S1. Start the closed-loop control of pressure and flow of the storage and supply unit; S2. Simultaneously turn on the neutralizer heating, contact power and neutralizer ignition power; S3. Perform normal ignition in the discharge chamber; after successful ignition, turn off the cathode heating and ignition power, and set the cathode flow rate to the normal flow rate. S4. After the discharge chamber is ignited, after a waiting time T1, the screen grid acceleration power supply is opened, and the external beam electric field replaces the contact electrode to draw out the neutralizer electrons. S5. Activate the flashing protection and increase the number of flashes within a preset time to the fault handling value; S6. Determine whether the accelerating current is less than or equal to the preset threshold. If so, determine that the neutralizer ignition is successful. S7. Ignition successful. Turn off the neutralizer heating and neutralizer ignition power.

2. A method for handling shorted or open circuit faults of a holding electrode in an electric propulsion thruster neutralizer according to claim 1, characterized in that: In S4, time T1 is from 350s to 420s.

3. A method for handling shorted or open circuit faults of a holding electrode in an electric propulsion thruster neutralizer according to claim 2, characterized in that: Time T1 is 390s.

4. A method for handling shorted or open circuit faults of a holding electrode in an electric propulsion thruster neutralizer according to claim 1, characterized in that: In S5, the fault handling value is 10 to 20 times.

5. A method for handling short or open fault conditions of a holding electrode in an electric propulsion thruster neutralizer according to claim 4, characterized in that: The fault handling value is 16 times.

6. A method for handling short or open fault conditions of a holding electrode in an electric propulsion thruster neutralizer according to claim 5, characterized in that: The preset time is 50s to 70s.

7. A method for handling short-circuit or open-circuit faults in the neutralizer contact poles of an electric propulsion thruster according to claim 6, characterized in that: The preset time is 60 seconds.

8. A method for handling short or open fault conditions of a holding electrode in an electric propulsion thruster neutralizer according to claim 1, characterized in that: In S6, the preset threshold is 21mA.

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